Entangled photon pairs from quantum dots embedded in a self-aligned cavity

TL;DR

This paper presents a scalable, self-aligned quantum dot-micro-cavity system that efficiently generates high-fidelity entangled photon pairs without complex fabrication steps, advancing quantum photonics applications.

Contribution

It introduces a novel self-aligned cavity platform that simplifies fabrication and significantly improves photon pair collection efficiency and entanglement fidelity.

Findings

Collection efficiency of 0.17 achieved, quadrupling previous state-of-the-art.

Purcell enhancement of up to 1.7 observed in pair emission.

Photon pairs generated with a fidelity of 0.84 in time bin entanglement.

Abstract

We introduce a scalable photonic platform that enables efficient generation of entangled photon pairs from a semiconductor quantum dot. Our system, which is based on a self-aligned quantum dot-micro-cavity structure, erases the need for complex steps of lithography and nanofabrication. We experimentally show collection efficiency of 0.17 combined with a Purcell enhancement of up to 1.7 in the pair emission process. We harness the potential of our device to generate photon pairs entangled in time bin, reaching a fidelity of 0.84(5) with the maximally entangled state. The achieved pair collection efficiency is 4 times larger than the state-of-the art. The device, which theoretically supports pair extraction efficiencies of nearly 0.5 is a promising candidate for the implementation of bright sources of time-bin, polarization- and hyper entangled photon pairs in a straightforward manner.